JP2940242B2 - Electron emission source and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron emission source used as a linear cathode of a fluorescent display tube or the like, and a method of manufacturing the same. In addition to the above, the present invention can be applied to a flat display device, a light emitting cell, a printer head, and the like utilizing the principle of a fluorescent display tube.

[0002]

2. Description of the Related Art An electron emission source used as a linear cathode of a fluorescent display tube or the like generally has an electron emission material layer attached around a core wire which generates heat when energized.
When vibration occurs in such a linear electron emission source, an image display is adversely affected. Therefore, in order to prevent the vibration, a support means may be brought into contact with the electron emission source.

[0003] If the support means is brought into direct contact with the electron emission material layer of the electron emission source, the electron emission material layer may be peeled off. For this reason, as shown in FIG.
An electron emission source 104 has been proposed in which a winding 101 is provided around 0, an electron emission material layer 102 is formed between the windings, and the winding is brought into contact with a support means 103.

In order to manufacture the above-described electron emission source 104, first, a winding 101 is wound around a core wire 100 as shown in FIG. Next, as shown in FIG. 3B, the electron emission material layer 1 is provided on the core wire 100 and the winding 101.
02 is deposited. Next, the projecting portion of the electron emitting material layer 102 is mechanically shaved off by using a peeling means (not shown), and a part of the winding 101 is exposed as shown in FIG.

[0005]

According to the above-described conventional electron emission source 104, there are the following problems. Since the electron emission source expands / contracts and vibrates due to heat, the electron emission material layer 1
02 is rubbed against the support 103 and
Collide with As a result, the electron-emitting substance peels off and is scattered in the display tube, thereby deteriorating the function of the display tube.

Since the electron emission material layer 102 is peeled off along the surface of the winding 101 by a mechanical means, the peeling is not uniform, and the windings 101 and 10 necessary for electron emission are removed.
One of the electron emitting material layers 102 is easily damaged. Therefore,
The deposition state of the electron emitting material is not uniform, and the electron emitting ability differs depending on the location.

Since the thickness of the electron emitting material layer 102 between the windings 101, 101 is the same as the diameter of the winding 101, the electron emitting material layer 102 comes into contact with the support 103 and peels off.

An object of the present invention is to provide an electron emission source in which the electron emission material between the windings is not easily peeled off even when it comes into contact with the support, and a method for manufacturing the same.

[0009]

The electron emission source according to the present invention comprises:
A core wire to be electrically heated; an electron emission material layer provided around the core wire and having a spiral groove formed on a peripheral surface thereof; and a spiral winding provided with a gap in the groove of the electron emission material layer. Line.

The method of manufacturing an electron emission source according to the present invention comprises the steps of: winding a winding covered with an organic insulating layer around a core wire; applying an electron emission material only to the core wire; Heating the core wire in a vacuum.

[0011]

The winding in contact with the support is wound in the groove formed in the electron emitting material layer of the core wire without being fixed to the electron emitting material. Therefore, even when the winding and the support come into contact with each other, an undesired force is hardly applied to the electron-emitting substance layer and the electron-emitting substance layer is hardly peeled off.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. The core wire 1 shown in FIG. 1A is made of tungsten or tungsten containing Re3%, and has a wire diameter of several μm to several tens μm. Here, the material is tungsten containing Re3%, and the wire diameter is 25 μm.

The winding 2 shown in FIG. 1A is made of tungsten or tungsten containing Re3%, and has a wire diameter of several μm.
To several tens of μm. Here, the material is tungsten,
The wire diameter is set to 8 to 10 μm.

An insulating layer 3 is provided around the winding 2. The material constituting the insulating layer 3 may be any insulating material that decomposes and evaporates when heated in a vacuum. In this case, an acrylic resin is used. Insulating layer 3
Although there is no particular limitation on the forming method, here, for example, a dipping method is used, and the material thickness is about several hundreds of .mu.m to 1 .mu.m.

As shown in FIG. 1A, the winding 2 covered with an insulating layer 3 made of acrylic resin is wound around the core 1 at a pitch of 75 μm to form a core 4.

Next, using the electrodeposition apparatus 11 shown in FIG.
An electron emission material layer 5 is applied to the core wire portion 4. An electrodeposition liquid 13 is stored in the electrodeposition tank 12. This electrodeposition liquid 1
3 is (Ba, Cr, Ca) CO which is a thermionic emission material
₍₃₎ Acrylic powder and electrolyte are dispersed and dissolved in acetone. The electrodeposition liquid 13 is sent into the tank by a pump 14 connected to the bottom of the electrodeposition tank 12, and is collected by the pump 14 by overflow. The linear core 4 can be immersed in the electrodeposition liquid 13 by the support roller 15 provided on the electrodeposition tank 12.

Next to the electrodeposition tank 12, an electrode tank 16 is provided. An electrolytic solution 17 containing barium nitrate is stored in the electrode tank 16. The linear core portion 4 can be immersed in the electrolytic solution 17 by a set of three introduction rollers 18 provided on the electrode tank 16.

The anode of the power source 19 is connected to the electrodeposition tank 12, and the cathode is connected to the electrode tank 16 adjacent to the electrodeposition tank 12. A support roller 20 is provided next to the electrodeposition tank 12 on the opposite side of the electrode tank 16.

The core wire portion 4 is wound around a drum-shaped sending device 21 and sent out into the electrode bath 16 and the electrodeposition bath 12. That is, the core wire portion 4 is guided by the introduction roller 18 and the support rollers 15 and 20, passes through the electrolyte solution 17 and the electrodeposition solution 13, and is further wound around the winder 23 through the dryer 22. Has become.

In the electrodeposition apparatus 11, the core portion 4 is transported by the feeder 21 and the take-up device 23, and is passed through the electrolyte solution 17 and the electrodeposition solution 13 while passing through the core portion 4. A DC electric field is applied between the electrodeposition tanks 12.
Since the winding 2 of the core 4 is covered with the insulating layer 3, it does not have a negative potential, and a negative potential is applied only to the core 1. Therefore, in the electrodeposition tank 12, (Ba, Sr, Ca) CO ₃ is deposited on the core 4 by the principle of electrophoresis.
And is not attached to the winding 2. By this step, as shown in FIG. 1B, a structure is obtained in which the insulating layer 3 of the winding 2 is spirally formed on the peripheral surface of the core wire 1 on which the electron emission material layer 5 is adhered. Note that the thickness of the electron emitting material layer 5 to be applied is set to be at least smaller than the diameter of the winding 2.

The core portion 4 obtained in the above-described process is mounted as a linear cathode in an envelope of a fluorescent display tube. Then, the interior of the envelope is evacuated to a high vacuum state, and the core 4 is heated and decomposed by energization to convert the carbonate into an oxide.

In this so-called writing process,
The insulating layer 3 covering the winding 2 of the core wire portion 4 is decomposed and evaporated, and a linear electron emission source 6 as shown in FIG. 1C is obtained. As shown in FIG. 1 (c), the winding 2 is not fixed to the electron-emitting material layer 5, but is wound with a gap in a spiral groove 7 formed in the electron-emitting material layer 5. Become. Further, as described above, the electron emission material layer 5 is formed.
Is smaller than the diameter of the winding 2, at least a portion of the winding 2 protrudes upward from the groove 7 of the electron emission material layer 5.

According to the electron emission source 6 of this embodiment, only the windings 2 projecting outward from the grooves 7 of the electron emission material layer 5 come into contact with the external support. And the winding 2 is
Although it is wound in the groove 7, it is not fixed to the electron emission material layer 5. Therefore, even if the electron emission source 6 vibrates or expands or contracts due to heat, an excessive force is not directly applied to the electron emission material layer 5 from the support. For this reason, the electron-emitting substance layer 5 does not easily peel off. In addition, the electron emission material layer 5
Are uniformly formed, so that there is no difference in electron emission characteristics depending on the location.

In the electrodeposition apparatus 11 used in this embodiment, the electrode bath 16 filled with the electrolytic solution 17 is provided in order to apply a negative potential to the core wire portion 4. The same purpose can be achieved by bringing the brush-like electrode into contact with the core wire portion 4.

[0025]

According to the present invention, the following effects can be obtained. Since the electron emitting material is not attached to the periphery of the winding and the winding and the electron emitting material are not directly fixed, even if the electron emitting source contacts the support, the electron emitting material is peeled off and the inside of the display tube is removed. No garbage.

Since it is not necessary to mechanically scrape off the electron-emitting substance deposited on the winding as in the related art, the electron-emitting substance can be uniformly deposited only on the core wire between the windings, so that a uniform A linear electron emission source is obtained.

If the thickness of the electron emitting material layer is smaller than the diameter of the winding, the contact between the winding and the support makes the electron emitting material layer and the support less likely to contact. Therefore, it is possible to reliably prevent the electron-emitting substance layer from peeling off and becoming dust.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a manufacturing process of an electron emission source according to an embodiment.

FIG. 2 is a schematic structural view of an electrodeposition apparatus used for manufacturing an electron emission source according to the present embodiment.

FIG. 3 is a cross-sectional view showing a manufacturing process of a conventional electron emission source.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Core wire 2 Winding 3 Insulating layer 5 Electron emission material layer 6 Electron emission source 7 Groove

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takehiro Niiyama 629 Oshiba, Mobara-shi, Chiba Futaba Electronics Co., Ltd. (58) Field surveyed (Int.Cl. ⁶ , DB name) H01J 31/15 H01J 1 / 16 H01J 9/04

Claims (3)

(57) [Claims] 1. A core wire to be electrically heated, an electron emitting material layer provided around the core wire and having a spiral groove formed on a peripheral surface, and a gap provided in the groove of the electron emitting material layer. An electron emission source comprising a spiral winding. 2. The electron emission source according to claim 1, wherein a thickness of the electron emission material layer is smaller than a diameter of the winding. 3. A step of winding a winding covered with an organic insulating layer around a core wire, a step of applying an electron emitting material only to the core wire, and a step of heating the core wire in a vacuum. Of manufacturing an electron emission source having the same.